Diabetes was first extensively described by Aretaeus of Cappadocia, and his contemporary, Galen of Pergamum, in the second century AD. Aretaeus is said to have introduced the term diabetes, though there are some indications of previous references to the term. When referring to the disease, Galen accepts that the term belongs to 'other writers'. There are, in fact, many other Graeco-Roman accounts of diabetes, and in this paper we also examine the texts of Pliny the Elder (first century AD), Rufus of Ephesos (early second century AD), Oribasius (fourth century AD), Stephanus Alexandrinus (fifth century AD), Aetius (sixth century AD), Alexander of Tralles (sixth century AD), and Theophilus Protospatharius (seventh century AD ), together with his contemporaries Paulus of Aegina, Stephanus of Athens and Leon of Pella (ninth century AD). All these writers use almost the same terminology when referring to the disease, and consider that symptoms of excessive thirst and urination are due to disease of the kidneys and the bladder. Similar treatments are also advocated, and relate to nutritional advice, herbal medications, poultices, bloodletting and abstinence from diuretic substances. Although there are no notable differences between the writings of Byzantine physicians and the earlier descriptions attributed to Aretaeus and Galen, this literature testifies to the fact that these physicians were well aware of a disease that Galen considered rare.